U.S. Pat. No. 6,233,150 discloses a memory module having a memory card with a circuit board and a number of electronic components mounted on the circuit board. The memory module has, as a heat sink, a pair of covers arranged on mutually opposite surfaces of the circuit board and a pair of clamps that press the two covers onto the circuit board. Each of the covers is thermally and electrically conductive and affords protection from electromagnetic radiation.
A complete heat sink of this type extends over all semiconductor devices of a memory module and thus thermally couples all of the semiconductor devices independently of their different power losses in a common housing. One disadvantage is impermissible heating of adjacent semiconductor devices. A further disadvantage is the high material outlay, which thus increases the costs, and, finally, there is the disadvantage that, in addition to producing the covers, it is also necessary to produce clamping elements in the form of clips, which increases the manufacturing costs.
U.S. Pat. No. 6,188,576 discloses a memory module having a housing cover in order to enclose a circuit board which has a plurality of individual semiconductor devices that dynamically generate different quantities of heat. The housing cover provides heat dissipation for the plurality of different memory chips. The different memory chips are thus thermally interconnected via the circuit board and via corresponding solder balls. Besides the heat dissipation, the rigid housing protects both the circuit board and the chips.
In an embodiment disclosed in U.S. Pat. No. 6,188,576, the memory module includes a thermally conductive substance arranged within the housing cover in order to conduct heat from the individual chips to the housing cover. The covers have snap-action hooks which reach over the edges of the circuit board and clamp the covers onto the circuit board from both sides. In this embodiment, there is also the risk of impermissible heating of adjacent semiconductor devices which intrinsically generate a reduced power loss and are then impermissibly additionally heated by the heat distribution of the thermally conductive substance and the thermally conductive covers. Moreover, here as well there is the disadvantage of an increased material outlay, which drives up the costs.